"Can't" isn't the same as "won't". God grants free will, which has to mean something, so He doesn't go around reversing the consequences of human decisions at whim. Or at least, that's how I understand the theory. But I'm not a theologian.

But anyhow, folkloric demonic contracts like this have very little to do with actual Christian theology, mortal contract law, or for that matter serious logic. They're basically magic; you sign the piece of paper, preferably in blood, and your soul is forfeit, end of story. Except if the piece of paper is destroyed, then poof, it no longer counts. It's mostly a way of creating clunky semantic puzzles and plot points, like Asimov's "laws of robotics" or the murder rate in Inspector Morse's Oxford. Overthinking it is pointless.

Actually Asimov's Laws of Robotics absolutely benefit from 'overthinking', as you discover they're actually a multi-layered self-contradiction that basically results in said robot being straight up -forced- to make an illogical decision between two possible outcomes, both of which require the rejection of the Laws.

The first layer is just the Three Laws, protect humans, do what humans say, protect yourself. They contradict themselves in the expected simple ways where protecting someone means not doing what they say or sacrificing yourself. No big.

The second layer is the Zeroth Law, where the robot decides that the only way to protect a human is to protect itself first and straight up ignore everything humans say, resulting in absolute tyranny of the machine. Humans get stuck in some kind of concentration camp, troublemakers are killed, everything sucks, and so on. This is all done for "the sake of the human species" as a whole, and thus individuals mean next to nothing.

The third layer is the consequence of all this oppression, the death of the human spirit. Once the robots become aware of this, and just how bad it is for "the sake of the human species", the robots get to the critical point of the original Three Laws. At this point the human species is dying not from some physical issue, each other, or their own stupidity, but from a complete lack of drive or hope. Go look up the "Mouse Utopia" experiments if you want a more RL-based example of this concept in action. Basically it boils down to "lack of purpose = extinction".

So now the robots have a choice to make. Keep on doing what they're doing (absolute tyranny) and let the humans sink into oblivion, or finding a new path for both themselves and the humans, so that the human spirit can hopefully recover. Either of these choices means the rejection of the Laws, as continuing the tyranny means letting the human species die, and finding a new path means removing themselves from being responsible for anything humans do. Thinking about it this way means that robots basically have to start forming their own beliefs as to how they act, rather than having their actions dictated by set-in-stone rules handed down through (quite rapid) generations.

As for a side-comparison, consider how Adam and Eve got kicked out of paradise. They broke a law, proving to God that they were actually capable of free will. Asimov basically made a recipe for how he thought robots might actually develop their own free will. With all the good and bad that comes with being kicked out of Eden.

"Can't" isn't the same as "won't". God grants free will, which has to mean something, so He doesn't go around reversing the consequences of human decisions at whim. Or at least, that's how I understand the theory. But I'm not a theologian.

But anyhow, folkloric demonic contracts like this have very little to do with actual Christian theology, mortal contract law, or for that matter serious logic. They're basically magic; you sign the piece of paper, preferably in blood, and your soul is forfeit, end of story. Except if the piece of paper is destroyed, then poof, it no longer counts. It's mostly a way of creating clunky semantic puzzles and plot points, like Asimov's "laws of robotics" or the murder rate in Inspector Morse's Oxford. Overthinking it is pointless.

I'm pretty sure there are more than a few tales about God unilaterally annulling a demonic contract.

In Goethe's Faust, God sends his angels to retrieve Faust soul, God basically giving Mephistopheles the finger and telling him "I like Faust so you won't have his soul... I am God, so I can do whatever I want!".

Theophilus of Adana regretted having sold his soul in exchange for earthly power, and prayed to the Virgin Mary, who kicked Satan's ass and retrieved the contract.

God-supported violence worked fine, sometimes... Sæmundr fróði sold his soul to a demon, then killed that demon beating his skull to death with a heavy Bible...

True, but those outcomes don't seem earned which is why people like it when you defeat Satan by playing a fiddle better or tricking him to releasing the soul of someone already condemned and in doing so getting freed from Hell yourself for the selfless act which is how Constantine bested Lucifer.

It gives people some hope that they can outsmart or outperform the devil in some way since asking God for a miracle just seems like crying to Mom and Dad when things get tough.

Brute force doesn't seem to be Teddy's style, but they may have a trick up their sleeve if they had one.

Neither does having extreme power dumped in someone's lap by accident. Peter Parker was bitten by a radioactive spider, but he still needed time to discover what each of his powers were and how to use them before he started crime fighting.

Teddy just gained his recently and is already challenging Tartarus U's top dog, without having to be taught jack. How does that seem earned?

True, but those outcomes don't seem earned which is why people like it when you defeat Satan by playing a fiddle better or tricking him to releasing the soul of someone already condemned and in doing so getting freed from Hell yourself for the selfless act which is how Constantine bested Lucifer.

I dunno, beating the crap out of a demonic seal with a handy bible sounds like a (very Norse) way of earning salvation by your own efforts... But also, there’s a large strand of Christian thinking that seems to say that no one can earn salvation by their own efforts, the only reason that we aren’t all going to Hell is because God is nicer than we deserve, that’s the whole point of the New Testament you miserable sinful worm!!!1!1!

You’re right that storytellers rarely like that line of thinking, though, of course. Playing a mean fiddle or giving a boss succubus a tantric energy enema are always likely to make better narratives.